The National Cancer Institute (NCI), Division of Cancer Prevention (DCP) Phase 0/I/II Cancer Prevention Clinical Trials Program supports early clinical trials to rapidly evaluate the clinical activity and biologic effects of cancer preventive agents. The agents to be studied include agents developed by the pharmaceutical industry and provided to DCP for collaborative development, commercially available agents, and agents developed by DCP. The program requires the establishment of a stable clinical trials infrastructure to support the accrual of approximately 75 or more subjects to phase 0-II clinical trials, with an emphasis primarily on phase II trials. Trials in multiple organ systems and with varying degrees of complexity will be performed. Clinical trials will be performed at the Contractors institution or at one or more collaborating institutions which enhance the capability of the Contractor to conduct these trials. The Contractor will be responsible for the oversight of all studies, including patient-level monitoring of accruing institutions.